Further to the above, I should add that due to a hip injury (and probably old age!), I >never< use the full pedal stroke. The beautiful thing about the Miragedrive is that it still works efficiently with less travel, and speed can be identical by increasing cadence. "Bottoming out" by hitting the hull at the end of a pedal stroke is bad for the drive as it causes forces to be applied to components outside their design parameters.

Having said that, however, I felt cramped in the standard seat, with pedals set at full extension, so I fitted a "skipper seat" which raised my backside by 4" and moved me back more than 2". I now use the middle pedal setting.

Wow what a great forum! Thank you guys for your very generous and prompt support on this knocking issue. By full extension I meant the pedals at their furthest distance apart. They are actually still on the 4 setting. The knocking only started on about the fourth voyage.

Kieran, The fins will hit the hull at the extreme of their travel (eg when the pedals are furthest apart). This is part of their design. If you move the pedal settings to 5, this should mean that when your leg is straightest, the fin will not quite reach the bottom of the hull.

However, it is possible to bang the fins against the hull with most pedal settings if you are too vigorous on the pedals! The thing to remember is that (as I mentioned earlier), the "stepper" style action of the Miragedrive works just as well with smaller steps, so as long as the fins don't bang on full stretch, there is no need to bring your knees up under your chin at the other end of travel.

I suspect the the problem showed up by about your fourth trip because your pedal stroke lengthened with familiarity, but you didn't notice. That's my theory and I'm sticking to it

I own a TI and am 6'4" 250 and my one son is 6'6" 260 and plays hockey, soooo, as Matt Miller suggested - your pedal stroke can affect the Mirage Drive.Trying to tell a college hockey player to limit his stride, …. well… Good Luck! Eventually stretched the cables where they couldn't be adjusted.

The symptoms - adjust both pedals to the same number, hold them together and see if the fins are aligned vertical??? Mine were skewed off to the side!

Went to dealer and we replaced the wire cables that have the nut clamped on the ends - back in business!

Thank you so much for sharing. I'm only 6' and 105kg but have strong cycling legs so this could be another factor. Now the wire did cross my mind and was hoping it wasn't bent. Tried the kayak yesterday and there seemed to be less knocking. The left of the two black levers which secure the turbo unit sometimes unlock and the unit rocks around a little. So I made sure to click it closed and the knocking seemed to disappear mostly. Would rather not have to repeatedly click it closed though.Thanks again. CheersKieran

If either lever comes undone, you can jam the drive in its slot if you pedal vigorously in this condition. I noticed that the levers stick up a little more on the AI, whereas they are flush with the floor on the TI. A friend has modified his AI slightly by drilling a horizontal hole through the top of the levers, and then attaching some light bungee cord to the centre black ring, with small hooks which pass through the holes in the levers. He just has to undo these hooks before trying to remove the Miragedrive. Hope this helps.

Tony is correct--pedaling when the drive is not locked in place risks jamming it. If that happens, it becomes a real problem to get it unjammed; although, even that gets easier w/ practice. It is best to be aware that the drive latches can be accidentally opened and immediately correct them in that event.

Keith

_________________2015 AI 2, 2014 Tandem

"Any intelligent fool can make things bigger and more complex ... It takes a touch of genius and a lot of courage to move in the opposite direction." A. Einstein

I'm 6' and I have my Mirage drive set to position 5 in the AI. In position 4 the fins strike the hull.

As others have said make sure you don't accidently unclick the click-n-go. Jamming the mirage drive is a PITA. Using a flat blade screwdriver to push down on the jammed locking lever is the easiest way to get your day back on track.

I really wish Hobie would fix this design fault on the Adventure / AI. I have almost been wiped out several times due to a jammed drive.